The Role of the Scanning Probe Microscopy in Nano-mechanical Testing
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Scanning probe microscopy in nano mechanical testing has started with the invention of the scanning tunneling microscope in the year 1981. Till then based on the type of principles there are number of models developed and are in use. Scanning probe microscopy found popularity owing to its ease in versatility in dealing with a number of issues, typically it is used to identify the material properties on nano to even pico scales. Scanning probe microscopy techniques such as atomic/friction force microscopy(AFM/FFM) are increasingly finding applications in tribological studies of engineering surfaces as well for finding surface texture etc. Atomic and molecular level details can be assessed using Scanning probe microscopy with…show more content… The spatial resolution used is far better than the wavelength used to create the image.
Scanning tunneling microscope is the first of the series of the scanning probe microscopes. The development of the family of scanning probe microscopes starts with the original invention of the STM in 1981. Gerd Binning and Heinrich Rohrer developed the first working STM in IBM. The STM works by scanning a very sharp metal wire tip over a surface. By brining the tip very close to the surface, and by applying an electrical voltage to the top or sample, we can image the surface at an extremely small scale-down to resolving individual atoms. The STM is based on several principles. One is the quantum mechanical effect of tunneling.
It is this effect that allows the viewer to visualize the target surface. Another principle is the piezo electric effect. It is this effect that allows us to precisely scan the tip with the angstrom- level control. Lastly a feedback loop is required, which monitors the tunneling current and co-ordinates the current and the positioning of the tip.
Tunneling current occurs when electrons move through a barrier that they classically should not able to move through. In classical terms if you don’t have enough energy to move over a barrier you won’t.